You're a Good Sport, Charlie Brown(1975)

Overview:

A motorcross, a race of motorbikes through a series of obstacles, provides the occasion for Charlie Brown's latest attempt to win at something. He selects Linus as his pit crew and goes to a store to select a bike, and due to insufficient funds, he must settle for a tiny, run-down putt-putt. The majority of Charlie's opponents are eliminated in the race, and Charlie, wearing a makeshift helmet carved from a pumpkin, finds himself in close competition with his friend, tomboy Peppermint Patty, and the Masked Marvel (a.k.a. Snoopy, Charlie's dog).